This invention relates to a variable point position determining arrangement especially as can be used for determining the position of a piston within a working cylinder. Such position determining arrangements, in addition to determining the position of the piston, can also be used to precisely control the stroke of the piston as a function of a predetermined value. Furthermore, such position determining arrangements, in addition to measuring the position and precisely controlling the stroke of a piston, can also be used to measure the position of any second point which is variable in relation to a first point which is fixed. Typically, it has been a well-known practice in this field to use a stepped-down gear unit driven by a geared rack connected to the piston rod as a means of measuring and controlling the position and stroke of the piston rod. Such an arrangement would require a potentiometer to be connected to the stepped-down gear unit which would give a signal as a function of the distance traveled by the piston rod. Such a configuration for the measuring of a piston position has the disadvantage of being relatively expensive. To guarantee smooth operation and a satisfactory precision of the apparatus, the gear wheels and the stepped-down gear unit and the geared rack must be manufactured to precise tolerances. But even with a very precise manufacture of the individual parts, such as, shafts, bearings, gear wheels and gear racks, imprecisions after a long-term operation cannot be entirely avoided since, over time, play develops between the gear wheels and at the bearing points. A further disadvantage of this existing configuration is the inability to operate where the movable object is moving in a nonaxial or curved manner. Such movement of the piston rod, for example, would result in a binding of the geared arrangement typically used by existing configurations.
Yet another disadvantage of existing configurations is the inability to adapt or be retrofitted to an existing working cylinder. To attempt to retrofit a gear-type measuring arrangement on a working cylinder would require extensive disassembly of that working cylinder and would therefore seem unreasonable.